390 Fortieth Annual Meeting 



most that can be said is that we have a mere circumstantial 

 suspicion against the chars and trouts, members of a family 

 with an excellent reputation. The case should be investi- 

 gated for several reasons, the least of which is that there 

 is any possibility that propagation increases the prevalence 

 of cancer. Other reasons are sufficient to lend importance 

 to thyroid disease in fishes. One controlling consideration 

 is that the chief source of knowledge of human cancer lies 

 now in the study of analogous processes in the lower 

 animals. Rats and mice and other mammals have been 

 largely used for this purpose. Fishes now open a fruitful 

 field for investigation on account of the complex nature 

 of the medium in which they live and its intimate 

 relation to human life and activity. That they 

 seem likely to supplement the warm-blooded animals and 

 furnish subjects in which by experiment the obscure cancer 

 process may be seen in a new light, is a cause of con- 

 gratulation to the medical profession and a source of some 

 consolation to the fish culturist. The experimenters will 

 look to fish culture for the necessary material in the form 

 of tumor bearing fishes. But fish culture has a further 

 interest in that it is responsible for breeding these fish and 

 should protect itself against even the suspicion of any evil 

 effect resulting. It is desirable that the whole subject be 

 investigated and it is appropriate that the Government as 

 one of the most active agents of propagation should under- 

 take the task. In this the province of the federal and state 

 organizations for fish culture, and the federal agencies of 

 public health seem to overlap. The pollution of public 

 waters, a menace requiring to be dealt with from both stand- 

 points, may be the keynote to the situation. It is pertinent 

 to cite again the rarity of thyroid disease in wild fish, its 

 frequency among domesticated, and to consider that the 

 few cases known among wild fish are from waters close to 

 civilization. Cancer is a disease of civilization. It is rare 

 among the American Indians, common among the whites. 

 The question of applying the term cancer to the thyroid 



